MINERALOGY OF FRANKLIN. 281 



the feldspar, in others the amphibole predominates ; 

 so that the rock presents all the shades which occur 

 between the well characterized sienite, and the 

 equally well characterized diabase or greenstone. 



The sienite of Franklin is found in beds or layers 

 of variable thickness, running in a direction parallel 

 to that of the ridge, from the north-east to the 

 south-west, consequently, parallel to the great Ap- 

 palachian chain of mountains, extending from the 

 southern part of the state of New York to Georgia. 

 The layers or beds incline to the south-east dipping 

 under an angle of about 80°. Subordinate to this 

 sienite, are found limestone, gneiss and greenstone ; 

 this latter being due of course to an accumulation of 

 amphibole, and diminution of feldspar, and forming 

 partial masses of no very great extent. 



The limestone forms a bed, without any apparent 

 parallel seams or divisions, and is peculiarly charac- 

 terized by its eminently crystalline structure, consist- 

 ing of large straight lamellar masses, confusedly ag- 

 gregated, appearing to belong to the eqaiaxe, from 

 the circumstance of its breaking into solids, which 

 present not only the cleavages of the primitive form, 

 but also those of this crystal ; the faces of the latter 

 are not, however, so well defined as those of the 

 former. It is of a fine white colour, presenting in 

 some instances a pearly lustre, slightly chatoyant ; 

 in short, a limestone admirably adapted to ornament- 

 al purposes, as a marble, for which at some future 

 time it will be used, notwithstanding the difficulty of 

 obtaining it in layers or plates. 



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